[DPE-4544] Fix model switch

[marceloneppel]

Issue

While setting the architecture constraints for the second model in the async replication tests through #464, it was missed to switch the model back to the first model. It caused issues because the juju offer command needed to be run in the first model on those tests.

FAILED tests/integration/ha_tests/test_async_replication.py::test_async_replication - juju.errors.JujuAPIError: application "async-primary" not found

This issue is blocking tests from passing on the main branch.

Solution

Switch the model back to the first model after setting the architecture constraints in the second model.

[taurus-forever]

I am not sure how the test passed in AMD before enabling ARM... but LGTM.

[lucasgameiroborges]

LGTM!

[marceloneppel]

I am not sure how the test passed in AMD before enabling ARM... but LGTM.

Before enabling ARM, we didn't have the first juju switch call (used to set the model constraints when in ARM), which caused the issue.